Method and apparatus to position and align pre-punched printing plates on an imaging cylinder

Abstract

An apparatus and method for positioning and aligning one or more pre-punched printing plates on a cylinder for imaging a plate in a computer-to-plate drum imaging device. The apparatus includes an imaging cylinder and a registration device connectable to the cylinder. The apparatus includes at least one groove and one pair of register pins, with a first register pin in a fixed position, and a second register pin movable in the groove to a second position, and collinear with the first register pin in the axial direction of the cylinder, arranged such that when connected to the cylinder, the registration device allows a plurality of pre-punched printing plates with variable widths to be positioned and aligned on the cylinder with simplicity.

I claim: 
     
       1. An apparatus comprising:
 an imaging cylinder for a computer-to-plate imaging device, the cylinder being rotatable around an axis, the rotation defining a circumferential direction, the axis defining an axial direction, the cylinder having a base body and an outer surface; and 
 a registration device connectable to the base body of the cylinder and when connected having an outer surface forming part of the outer-surface of the cylinder, the registration device arranged to position and align one or more pre-punched printing plates on the outer surface of the cylinder, 
 wherein the registration device when connected includes: 
 a groove extending axially on the outer surface of the cylinder, and forming a gap on the outer surface of the cylinder, 
 a first register pin having a fixed position on the base body of the cylinder, and 
 a second register pin movable in the groove and after being moved to a next position on the base body of the cylinder, being fixable to the next position, 
 wherein the first register pin is insertable into a first hole of a printing plate to provide a starting point for the plate, and 
 wherein the second register pin is insertable into a second hole of the plate when the first register pin is inserted into the first hole, the second hole being at a plate position dependent on the width of the plate and defining, when the first register pin is inserted into the first hole and connected to the fixed position, a second position in the axial direction on the outer surface of the cylinder, the second register pin being insertable into the second hole after being moved to the second position, and being fixable to the second position to position the plate on the outer surface of the cylinder. 
 
     
     
       2. An apparatus as recited in  claim 1 , wherein the groove has a reverse T-shaped cross-section. 
     
     
       3. An apparatus as recited in  claim 1 , wherein the fixed position is a position in the axial direction in the groove. 
     
     
       4. An apparatus as recited in  claim 3 , wherein the first register pin is fixed into the groove using a lock screw. 
     
     
       5. An apparatus as recited in  claim 1 , wherein the first register pin and the second register pin in combination can position and align printing plates of different widths on the outer surface of the cylinder. 
     
     
       6. An apparatus as recited in  claim 1 , wherein the registration device includes a plurality of pairs of register pins, each pair including a first register pin having a fixed position on the outer surface of the cylinder and a second register pin being movable in the groove to provide a variable position on the outer surface, all the fixed and variable positions being collinear along the axial direction, such that a plurality of pre- punched printing plates can be positioned and aligned on the outer surface of the cylinder for operating the imaging device while the plurality of plates are on the outer surface of the cylinder at the same time. 
     
     
       7. An apparatus as recited in  claim 6 , wherein the registration device includes a plurality of grooves, and wherein there is at least one pair of register pins in each groove. 
     
     
       8. An apparatus as recited in  claim 1 , further comprising at least one registration device arranged at a different circumferential location of the cylinder. 
     
     
       9. An apparatus as recited in  claim 1 , wherein the groove is formed by a register bar that is connected into the base body of the cylinder. 
     
     
       10. An apparatus as recited in  claim 9 , wherein the register bar can be replaced with a bar having no groove to close the gap on the outer surface of the cylinder. 
     
     
       11. A method comprising:
 arranging one or more pre-punched printing plates on an imaging cylinder for a computer-to-plate imaging device, the cylinder being rotatable around an axis, the axis defining an axial direction, the cylinder having a base body and an outer surface; for each of the plates, 
 inserting a first register pin into a first hole of the plate, the first register pin having a first position on the base body of the cylinder, the first position being a fixed position providing a starting point for the plate; 
 connecting the first register pin to the fixed position; 
 moving a second register pin to a second position on the base body of the cylinder, the second register pin being movable in a groove extending axially on the outer surface of the cylinder, the second position being in the groove and being determined by a second hole of the plate after the first register pin is inserted into the first hole and connected to the fixed position, the second hole being at a plate position dependent on the width of the plate; 
 inserting the second register pin into the second hole of the plate and connecting the second register pin to the second position; and 
 fixing the first register pin into the first position and the second register pin into the second position; 
 such that when the first register pin and the second register pin are fixed into the respective positions, the plate is positioned on the outer surface of the cylinder. 
 
     
     
       12. A method as recited in  claim 11 , wherein the groove has a reverse T-shaped cross-section. 
     
     
       13. A method as recited in  claim 11 , wherein the fixed position is a position in the axial direction in the groove. 
     
     
       14. A method as recited in  claim 11 , wherein the first register pin and the second register pin in combination can position and align printing plates of different widths on the outer surface of the cylinder. 
     
     
       15. A method as recited in  claim 11 , wherein multiple pre-punched printing plates are positioned on the outer surface of the cylinder using a plurality of pairs of register pins, each pair including a first register pin having a fixed position on the outer surface of the cylinder and a second register pin being movable in the groove to provide a variable position on the outer surface, all the fixed and variable positions being collinear along the axial direction, such that the multiple plates are aligned on the outer surface of the cylinder for operating the imaging device while the plates are on the outer surface of the cylinder at the same time. 
     
     
       16. A method as recited in  claim 15 , wherein the multiple printing plates have same widths. 
     
     
       17. A method as recited in  claim 15 , wherein at least two printing plates have different widths. 
     
     
       18. A method as recited in  claim 15 , wherein there is a plurality of grooves, and wherein there is at least one pair of register pins in each groove. 
     
     
       19. A method comprising:
 preparing a groove on an imaging cylinder used in a computer-to-plate imaging device, the cylinder being rotatable around an axis, the axis defining an axial direction, the cylinder having a base body and an outer surface, the groove extending axially on the outer surface of the cylinder, and forming a gap on the outer surface of the cylinder; 
 preparing a first register pin at a fixed position on the outer surface of the base body of the imaging cylinder, the first register pin being insertable into a first hole of a printing plate that includes two or more holes, including a second hole, to provide a starting point for the plate; and 
 preparing a second register pin that is movable in the groove such that the second register pin location is variable, the second register pin being insertable into the second hole of the plate when the first register pin is inserted into the first hole, the second hole being at a plate position dependent on the width of the plate and defining, when the first register pin is inserted into the first hole and connected to the fixed position, a second position in the axial direction on the outer surface of the cylinder, the second register pin being insertable into the second hole and fixable to the second position after the second pin is moved to the second position on the outer surface to position the plate on the outer surface of the cylinder, such that different plates of varying width may be mounted on the outer surface at a location determined by the first fixed register pins and at least the second register pin. 
 
     
     
       20. A method as recited in  claim 19 , wherein the groove is formed by a register bar that is connected into the base body of the cylinder and that includes the groove.